Refractory block for annular linings



Aug. 26, 1969 E. M. SARRAF' 3,463,365

REFRACTORY BLOCK FOR ANNULAR LININGS Filed Jan. 5, 1967 I5 5 Fig. 2

' //Vl E/V7'A. 3 [an/4P0 M SAP/84F A TTOR/VE) United States Patent3,463,865 REFRACTORY ,BLOCKFOR ANNULAR LININGS Edward M. Sarraf, 22290Blossom Drive, Rocky River, Ohio 44116 Filed Jan. 3, 1967, Ser. No.606,944 Int. Cl. Hk 5/12, 5/02 US. Cl. 13-35 2 Claims ABSTRACT OF THEDISCLOSURE Refractory linings for barrel type channel furnace inductionfurnaces and other vessels having an annular refractory lining. Theshapes are characterized as having generally opposed curved sidesurfaces, opposed end surfaces and opposed face surfaces. The shapescontain complementary tongues and grooves in opposed face surfacesextending between the opposed side surfaces and also between the opposedend surfaces.

The shapes of the present invention are primarily designed for use inbarrel type channel induction furnaces where the problem is most acute.Channel induction furnaces are used throughout the ferrous andnonferrous metals industries for melting and holding hot metals. Theyare used primarily in foundries because of the close temperature controlthey provide and the need for such control in foundry casting.Furthermore, they are extremely economical as their electricalefficiencies approach 97%; and, among other advantages, they operatedirectly from standard frequency power lines.

The basic design for most channel induction furnaces is a hearth forholding the hot metal and at least one inductor block. The hearth of abarrel type inductor furnace generally has a cylindrical wall and twoend walls perpendicular to the cylindrical axis about which the wholefurnace rotates. On the cylindrical wall, there is at least one door forcharging scrap and removing slag. Generally opposite the charging doorin the cylindrical wall, there is at least one openingor throat. Theinductor blocks are releasably attached to the cylindrical wall incommunication with the throat. Regardless of how many inductor blocksand charging doors are used, at least one charging door and one inductorblock are positioned so that hot metal can be poured directly into aninductor block. This is necessary to start up a cold furnace. Spouts forcharging and removing hot metals are usually joined to the end walls ofthe hearth. The walls of the hearth consist of an outer metal shellwhich is lined with refractory brick and monolithic materials.

In all furnaces of which I am aware, the inductor block linings receivesevere wear. This is because the temperatures are higher in the inductorblocks than elsewhere, and metal is continuously drawn through therestricted inductor channel tending to erode or wash away refractorysurfaces. For this reason, inductor blocks are releasably attached tothe hearth so they can periodically be removed and relined.

In the hearth of an induction furnace there are several severe wearareas. The area adjoining the inductor blocks referred to as throats,are often consumed before the rest of the hearth for the same reasonsthe inductor blocks are rapidly consumed. Another reason fordeterioration of the throat area is the difficulty in providing astructurally integral refractory lining adjacent the throats to holdthem securely in place.

According to this invention, it is possible to line a large barrel typeinduction furnace with brick such that, as the throat area is worn awayor periodically replaced, the rest of the lining remains snugly inplace.

Therefore, it is an object of the present invention to 3,463,865Patented Aug. 26, 1969 provide a structurally integral arcuaterefractory lining for barrel type induction furnaces and the like.

According to one aspect of this invention, a refractory lining isprovided for a barrel type channel induction furnace having a generallycylindrical metal shell, and two end walls, at least one opening in theshell for charging, and at least one throat opening through an inductorblock generally opposite the charging door. The lining is composed of aplurality of adjacent annular courses of refractory brick having opposedface surfaces transverse to the shell, opposed end surfaces and opposedside surfaces. The opposed side surfaces are also referred to as the hotface and cold face, the cold face being adjacent the metal shell and thehot face open to the interior of the furnace. The end faces are joinedto adjacent brick in each course. The refractory brick containcomplementary tongues and grooves in the face surfaces extending betweenopposed side surfaces. It is preferred that the brick also containcomplementary tongues and grooves in opposed face surfaces extendingbetween the opposed end surfaces. The brick are arranged so that thetongues and grooves are complementarily mated with the brick in"adjacent courses to provide a continuous tongue and groove jointconcentric with the metal shell and also one transverse to the metalshell.

Further features and other objects and advantages of this invention willbecome clear to those skilled in the art by the study of the followingdetailed description with reference to the drawings in which:

FIGS. 1 and 2 are an isometric view of the novel shapes employed in thepresent invention: and

FIG. 3 is a cross sectional view of the hearth of a barrel type channelinduction furnace.

Referring to the drawings, the hearth of the barrel type inductionfurnace is contained in an outer metal shell 1 which is generallycylindrical. Adjacent the other metal shell is a refractory lining 3.The lining maybe divided into a separate insulating lining and a workinglining if desired. There is a charging door (not shown) and slagremoving door (not shown) located in the cylindrical wall of the hearth.There is a throat 5 generally opposite the charging door. As shown inFIG. 3, the working lining 3 is lined with the refractory shapes 5 ofthis invention. The shape 5 may be used in each course of the annularlining and are keyed or tightened together with wedge shape brick 7. Fordetails on the design of a typical barrel shaped channel inductionfurnace, attention is directed to United States patent application, Ser.No. 572,563.

The shapes used in the lining of the induction furnace are shown inFIGS. 1 and 2. The shape 5 consists of opposed end surfaces 9' and 11,opposed curved side surfaces 13 and 15 and opposed face surfaces 17 and19. One of the face surfaces 17 contains a plurality of tongues 21extending between the side surfaces and a plurality of tongues 23extending between the end surfaces. The other opposed face 19 contains aplurality of complementary grooves 25 extending between the opposed sidesurfaces and a plurality of complementary grooves 27 extending betweenthe opposed end surfaces. The tongues and grooves on the faces of thebrick are complementarily mated with the tongues and grooves of adjacentbrick along the annulus of the kiln to provide an integral and unitarylining. Further, to insure the interlocking of the brick along theannulus and to prevent their displacement by the force of gravity, thejoints in each course of brick are staggered with respect to an adjacentcourse.

It is intended that the foregoing descriptions and drawings be construedas illustrative and not in limitation of the invention.

Having thus described the invention in detail and with suificientparticularity as to enable those skilled in the art to practice it, whatis desired to have protected by Letters Patent is set forth in thefollowing claims.

-I claim:

1. A rotatably mounted barrel shaped channel induction furnacecomprising a generally cylindrical metal shell closed by end Walls, arefractory lining adjacent the shell, said lining composed of aplurality of adjacent courses of refractory brick having generallyopposed curved side surfaces, and opposed ends extending between a pairof opposed face surfaces, said face surface of each brick being providedwith complementary tongues and grooves extending between opposed sidesurfaces, said face surface of each brick being provided with at leastone complementary tongue and groove extending between opposed endsurfaces, said brick being disposed so that a side surface is adjacentthe metal shell and the tongues and grooves are complementarily matedwith 4 brick in adjacent courses to provide an integral lining. 2. Aninduction furnace according to claim l in which each brick coursecontains a plurality of joints which are staggered with respect to anadjacent course.

References Cited V UNITED STATES PATENTS BERNARD A. GILHEANY, PrimaryExaminer 15 R. N. ENVALL, JR., Assistant Examiner US. Cl. X.R. 266-43

